Communication devices such as mobile stations (MS) are also known as e.g. user equipments (UE), terminals, mobile terminals, wireless terminals, and/or wireless devices. MSs are enabled to communicate wirelessly in a cellular communications network or wireless communication system, sometimes also referred to as a cellular radio system or cellular networks. The communication may be performed e.g. between two MSs, between a MS and a regular telephone and/or between a MS and a server via a Radio Access Network (RAN) and possibly one or more core networks, comprised within the cellular communications network.
MSs may further be referred to as mobile telephones, cellular telephones, laptops, tablet computers or surf plates with wireless capability, just to mention some further examples. The MSs in the present context may be, for example, portable, pocket-storable, hand-held, computer-comprised, or vehicle-mounted mobile devices, enabled to communicate voice and/or data, via the RAN, with another entity, such as another MS or a server.
The cellular communications network covers a geographical area which is divided into cell areas, wherein each cell area being served by a radio network node. A cell is the geographical area where radio coverage is provided by the radio network node.
The radio network node may e.g. be a base station such as a Radio Base Station (RBS), eNB, eNodeB, NodeB, B node, or Base Transceiver Station (BTS), depending on the technology and terminology used. The base stations may be of different classes such as e.g. macro eNodeB, home eNodeB or pico base station, based on transmission power and thereby also cell size.
Further, each radio network node may support one or several communication technologies. The radio network nodes communicate over the air interface operating on radio frequencies with the wireless terminals within range of the radio network node. In the context of this disclosure, the expression Downlink (DL) is used for the transmission path from the base station to the MS. The expression Uplink (UL) is used for the transmission path in the opposite direction i.e. from the MS to the base station.
With the rapid MS evolution, there is also a rapid increase in the need for additional processing power in the MSs to support more and more advanced radio network features, such as dual and multi-carrier reception.
A resource block comprises information transmitted within a limited time duration, using a fixed bandwidth in the frequency domain. The limited time duration is e.g. a given timeslot (TS) within a Time Division Multiple Access (TDMA) frame, where each TDMA frame is received within the context of repeated 52-multiframes in General Packet Radio Service (GPRS)/Enhanced Data rates for Global Evolution (EDGE) systems. The fixed bandwidth in the frequency domain is e.g. a radio frequency carrier that supports repeated 52-multiframes on one or more TS in GPRS/EDGE systems.
A MS will have the ability to process a certain maximum number of resource blocks based on the limitations of its processing power, e.g. 20 TSs received on a maximum of 8 radio frequency channels in GPRS/EDGE systems.
The processing power of the MS is typically signaled from the MS to the network in one way or the other. In a Global System for Mobile Communications (GSM) system the processing power is signaled to a Base Station Controller (BSC) and/or a Serving GPRS Support Node (SGSN).
Downlink Dual Carrier (DLDC) is a feature introducing two parallel carriers transmitted on the DL to the same MS. In DLDC, a single carrier transmission is extended to two separate carriers transmitted in parallel.
DLDC is limited to the reception of at most two carriers in the DL. The carriers are received in separate receivers and hence the performance of each carrier is identical to reception of one single carrier. The number of carriers is limited to two due to cost, complexity and size reasons. Adding more carriers implies adding more receive chains which will increase cost and complexity, but also the size of a receiving device, such as the MS.
A feature supporting multiple carriers on a DL, Downlink Multi Carrier (DLMC), is currently being standardized in Third Generation Partnership Project (3GPP) GSM/EDGE Radio Access Network (GERAN). DLMC utilizes a wide receiver filter and a single receive chain to simultaneously receive multiple carriers. Adding more carriers to the reception does not impost and implications on cost of the receiver and does not impact the size of the device. When using DLMC, the main limitation of the number of resources possible to process by a device, such as a MS, is its processing power.
In current GSM functionality, the number of DL resource blocks that can be simultaneously processed by an MS during each Transmission Time Interval (TTI), is determined by a signaled multislot class, a signaled maximum number of carriers supported, and a reduction parameter. The multislot class indicates the maximum number of DL timeslots that an MS can receive on a DL carrier during a TTI. The indicated maximum number of carriers supported is one or more of single carrier, dual carrier or multi carrier. Dual carrier and multi carrier are explicitly indicated, whereas single carrier does not require an explicit indication. The reduction parameter defines a reduction in the total number of TS and is currently indicated in an Information Element (IE) named Multislot Capability Reduction for Downlink Dual Carrier. The value of this parameter is subtracted from the product of the maximum number of DL TS according to the multislot class and the maximum number of carriers supported. A network node, such as a BSC will assign resource blocks to the MS, based on the above described signaled multislot class, maximum number of carriers and reduction parameter. This kind of capability signaling was developed in order to comply with DLDC operation.